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Filters: Tags: Projecting Future States 1-Predict or Map the Impact of Changing Permafrost (X)

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Ongoing and rapid environmental change within western and northern Canada is of major societal and scientific concern and has local- to global-scale implications. There is an urgent need to understand the changes and develop improved diagnostic and predictive modeling tools to manage uncertain futures.
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In glacier-fed systems climate change may have various effects over a range of time scales, including increasing river discharge, flood frequency and magnitude. This study uses a combination of empirical monitoring and modelling to project the impacts of climate change on the glacial-fed Middle Fork Toklat River, Denali National Park, Alaska. We use a regional calibration of the model HBV to account for a paucity of long term observed flow data, validating a local application using glacial mass balance data and summer flow records. Two Global Climate Models (HADCM3 and CGCM2) and two IPCC scenarios (A2 and B2) are used to ascertain potential changes in meteorological conditions, river discharge, flood frequency...
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The boreal forests of North America are undergoing major changes because of the direct effects of global warming and increased CO sub(2) levels. Plant production in the boreal forest is nutrient limited, and we examined how long-term fertilization affected growth of white spruce Picea glauca in the face of these major changes. We conducted a large-scale experiment by fertilizing two 1 km super(2) stands of white spruce in the southwestern Yukon with commercial NPK fertilizer from 1987 to 1994. Tree growth was measured by the width of annual increments in 60 trees from each of 2 control and of 2 matched fertilized 1 km super(2) sites for the period from 1977 to 1997 in a before, during, and after experimental design....
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Old Crow Flats is a 5600 km2 glaciolacustrine plain that straddles the forest-tundra ecotone in northern Yukon. Continuous taiga corridors occur in the entrenched river valleys, where annual mean ground temperatures (Tg) at the depth of zero annual amplitude at two locations were ?3.1 and ?4.0ºC in 2013. On the Flats, the vegetation cover is patchy, and Tg varied between ?5.1 and ?2.6ºC. Annual mean near-surface permafrost temperatures (Tps) measured on the Flats between 2008 and 2011 in patches of taiga, tall shrubs and low shrubs were correlated with local snow depth. Snow depth was controlled by vegetation height if the snow supply was not limited, for example, where low shrubs and large lakes dominate the landscape....
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Discontinuous permafrost in the North American boreal forest is strongly influenced by the effects of ecological succession on the accumulation of surface organic matter, making permafrost vulnerable to degradation resulting from fire disturbance. To assess factors affecting permafrost degradation after wildfire, we compared vegetation composition and soil properties between recently burned and unburned sites across three soil landscapes (rocky uplands, silty uplands, and sandy lowlands) situated within the Yukon Flats and Yukon-Tanana Uplands in interior Alaska. Mean annual air temperatures at our study sites from 2011 to 2012 were relatively cold (-5.5 degrees C) and favorable to permafrost formation. Burning...
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This article is one of a series of papers published in this CJES Special Issue on the theme of Fundamental and applied research on permafrost in Canada.
This thesis outlines the development of the timescales, the calibration of the ice-climate relationships, and the possible linkages between the Quelccaya Summit Ice Core and the Bona Churchill Ice Core, with different modes of decadal and interannual climate variability during the last 1,000 years. The timescale for BC1 is well constrained during the last 1,000 years by annual layering, the identification of the 1963 β-peak, the 1912 eruption of Katmai, and the 1783 eruption of Laki. Additionally, this study pinpoints the period A.D. 760 to 777 (according to the BC1 timeline) as the likely timing of the White River Ash, an important regional chronostratigraphic marker. The timescale for the 2003 Quelccaya Summit...
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Solifluction lobe process and morphology were studied on an alpine slope (1800 m a.s.l) above Kluane Lake, south-western Yukon Territory. Contemporary rates of surface movements, measured by theodolite survey, were found to be greatest in the first two weeks of spring thaw, and movements were consistently faster on lobe treads than on lobe risers. Precise monitoring of thaw-consolidation parameters on a lobe indicated that most thaw-settlement occurred when the soil was saturated to the surface. At the slope scale, surface rates increased downslope in response to gradients in soil moisture, while long-term rates of lobe advance, inferred from 14 C dating of buried organic horizons, were found to be similar among...
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To better understand the linkage between lake area change, permafrost conditions and intra-annual and inter-annual variability in climate, we explored the temporal and spatial patterns of lake area changes for a 422?382-ha study area within Yukon Flats, Alaska using Landsat images of 17 dates between 1984 and 2009. Only closed basin lakes were used in this study. Among the 3529 lakes greater than 1 ha, closed basin lakes accounted for 65% by number and 50% by area. A multiple linear regression model was built to quantify the temporal change in total lake area with consideration of its intra-annual and inter-annual variability. The results showed that 80.7% of lake area variability was attributed to intra-annual...
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The Fairbanks Permafrost Experimental Station was established in 1945 near Fairbanks, Alaska. In 1946 vegetation was removed from two plots (the Linell plots) to investigate the impacts of vegetation disturbance on permafrost degradation. We revisited the sites in 2007 to evaluate the permafrost table using probes and direct current electrical resistivity. The permafrost table has expanded downward to 9.8 m at a site where all surface vegetation and organic material was removed. The permafrost surface has remained at 4.7 m depth since 1972 at a second site where vegetation was removed but organic material was left intact. In 2005 a Circumpolar Active Layer Monitoring Network (CALM) site was established at an undisturbed...
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In Canada's western Arctic, perennial discharge from permafrost watersheds is the surface manifestation of active groundwater flow systems, yet understanding the mechanisms of groundwater recharge and flow in periglacial environments remains enigmatic. This thesis addresses questions on how and where groundwater recharge occurs. Watersheds were selected in Yukon (Fishing Branch River at Bear Cave Mountain) and the Northwest Territories at latitudes spanning from continuous to discontinuous permafrost (five tributary rivers to the Mackenzie River from Wrigley to Aklavik). All are characterized by perennial flow with open water in the winter, and discharge from sedimentary formations of karstic carbonates and evaporate...


map background search result map search result map Observation, Diagnosis, and Prediction of Environmental Change in Northwestern Canada Temporal and spatial pattern of thermokarst lake area changes at Yukon Flats, Alaska Vegetation-Permafrost Relations within the Forest-Tundra Ecotone near Old Crow, Northern Yukon, Canada Climate and ground temperature relations at sites across the continuous and discontinuous permafrost zones, northern Canada More comprehensive characterization of landslides in permafrost Edaphic and microclimatic controls over permafrost response to fire in interior Alaska The Significance of Shifts in Precipitation Patterns: Modelling the Impacts of Climate Change and Glacier Retreat on Extreme Flood Events in Denali National Park, Alaska Characteristics of discontinuous permafrost based on ground temperature measurements and electrical resistivity tomography, southern Yukon, Canada Soil CO (sub 2) production in upland tundra where permafrost is thawing A spatially explicit analysis to extrapolate carbon fluxes in upland tundra where permafrost is thawing Permafrost dynamics at the Fairbanks Permafrost Experimental Station near Fairbanks, Alaska Climate and nutrient influences on the growth of white spruce trees in the boreal forests of the Yukon The effect of permafrost thaw on old carbon release and net carbon exchange from tundra Development of solifluction lobes, Kluane Range, Yukon Territory Climate Change Trends for the State of the Park Report, Denali National Park, Alaska Geochemistry and noble gases of permafrost groundwater and ground ice in Yukon and the Northwest Territories, Canada The effect of permafrost thaw on old carbon release and net carbon exchange from tundra Soil CO (sub 2) production in upland tundra where permafrost is thawing A spatially explicit analysis to extrapolate carbon fluxes in upland tundra where permafrost is thawing Development of solifluction lobes, Kluane Range, Yukon Territory Climate and nutrient influences on the growth of white spruce trees in the boreal forests of the Yukon Permafrost dynamics at the Fairbanks Permafrost Experimental Station near Fairbanks, Alaska Climate Change Trends for the State of the Park Report, Denali National Park, Alaska Edaphic and microclimatic controls over permafrost response to fire in interior Alaska Temporal and spatial pattern of thermokarst lake area changes at Yukon Flats, Alaska Geochemistry and noble gases of permafrost groundwater and ground ice in Yukon and the Northwest Territories, Canada Characteristics of discontinuous permafrost based on ground temperature measurements and electrical resistivity tomography, southern Yukon, Canada The Significance of Shifts in Precipitation Patterns: Modelling the Impacts of Climate Change and Glacier Retreat on Extreme Flood Events in Denali National Park, Alaska Vegetation-Permafrost Relations within the Forest-Tundra Ecotone near Old Crow, Northern Yukon, Canada Observation, Diagnosis, and Prediction of Environmental Change in Northwestern Canada Climate and ground temperature relations at sites across the continuous and discontinuous permafrost zones, northern Canada More comprehensive characterization of landslides in permafrost